Has a variable territory depending on the size of the AICA.Bilateral cerebellar infarcts in posterior inferior cerebellar artery (PICA) territories have been previously reported and the common PICA (c-PICA) on one side was proposed as a possible mechanism. small perforating medullary branches (absent in 50%). anterior and lateral medullary segments.This point has a constant relationship with the 4th ventricle and was used prior to crossectional imaging to asses for shift in its position. junction between the posterior medullary segment and the supratonsillar segment is upwardly convex and is the site of origin of small choroidal branches: it is known as the "choroid point".ascends posterior to the medulla behind CN IX and CN X and along the posterior medullary velum.curves forming the 'caudal loop' which is located anteroinferior to the tip of the cerebellar tonsil between the origins of the vagus and the accessory nerve.from its origin around the inferior aspect of the medullary olive.occasionally loops around the cerebellar tonsilīranches from this artery supply the choroid plexus of the fourth ventricle.10% arise from the basilar rather than vertebral artery.18-20% arise extracranially, inferior to the foramen magnum.Its origin is usually the vertebral arteries intracranially but variations include: Posterior inferior cerebellar artery (PICA) is one of the three vessels that provide arterial supply to the cerebellum. Occlusion of AICA results in lateral pontine syndrome, also known as AICA syndrome., which involve sudden onset vertigo and vomiting, nystagmus (due to damage to vestibular nuclei), ipsilateral loss of sensation of the face (due to damage to principal sensory trigeminal nucleus), ipsilateral facial paralysis (due to damage to the facial nucleus) and ipsilateral hearing loss and tinnitus (due to damage to the cochlear nuclei). Extra-axial masses (e.g. acoustic schwannomas or meningiomas) would displace the vessel whereas intra-axial masses tend not to. medial branch supplies the biventral lobuleīefore cross-sectional imaging, the AICA (along with venous displacement) was used to identify posterior fossa intra- or extra-axial masses especially at the CP angle.lateral branch passes around the flocculus and into the hemispheric fissure (supplying both superior and inferior semilunar lobules).internal auditory branch (80% single, 20% double) passes into the internal acoustic meatus.It passes backwards to the anterior surface of the cerebellum. anteroinferior surface of the cerebellumĩ9% of AICAs arise from the basilar artery with around 75% coming from the lower third.It has a variable origin, course and supply, with up to 40% of specimens not having an identifiable standard AICA due to PICA-AICA dominance. The anterior inferior cerebellar artery (AICA) is another vessels that provides arterial blood supply to the cerebellum. anastomose with inferior vermian branches of the PICA.arise from the lateral (marginal) branch and from the SCA distal to the origin of the lateral branch also from the ambient segment.gives off hemispheric branches that course superiorly over the superior cerebellar hemisphere.runs posteriorly in the region of the interhemispheric fissure.usually arises from the ambient segment.quadrigeminal segment: continues on the upper surface of the cerebellum.ambient segment: winds around the cerebral peduncle, close to the trochlear nerve.prepontine segment: It passes lateralward, immediately below the oculomotor nerve, which separates it from the posterior cerebral artery.The upper branch, when multiple, may arise from the PCA and usually supplies the vermis, whereas the lower branch supplies the hemisphere. Unlike the anterior inferior cerebellar artery (AICA) and posterior inferior cerebellar artery (PICA) the SCA is usually present but, it is frequently duplicated: inferior colliculus by the quadrigeminal segment) whole superior surface of the cerebellar hemispheres down to the great horizontal fissure.The superior cerebellar artery (SCA) arises from the distal basilar artery, just below the posterior cerebral artery (PCA) and typically supplies the superior half of the cerebellum, and the midbrain.
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